DOE OSTI2020
BaPr3(NiO4)2 is (La,Ba)CuO4-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.53–2.78 Å. There are three inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 1-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.35–2.80 Å. In the second Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.38–2.77 Å. In the third Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.37–2.80 Å. There are two inequivalent Ni+2.50+ sites. In the first Ni+2.50+ site, Ni+2.50+ is bonded to six O2- atoms to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Ni–O bond distances ranging from 1.97–2.30 Å. In the second Ni+2.50+ site, Ni+2.50+ is bonded to six O2- atoms to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Ni–O bond distances ranging from 1.90–2.34 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to five Pr3+ and one Ni+2.50+ atom. In the second O2- site, O2- is bonded to one Ba2+, four Pr3+, and one Ni+2.50+ atom to form distorted OBaPr4Ni octahedra that share corners with seventeen OBaPr3Ni2 octahedra, edges with four OBa2Pr3Ni octahedra, and faces with four equivalent OBaPr3Ni2 octahedra. The corner-sharing octahedra tilt angles range from 0–55°. In the third O2- site, O2- is bonded to two equivalent Ba2+, three Pr3+, and one Ni+2.50+ atom to form distorted OBa2Pr3Ni octahedra that share corners with seventeen OBaPr3Ni2 octahedra, edges with six OBaPr4Ni octahedra, and faces with four equivalent OBaPr3Ni2 octahedra. The corner-sharing octahedra tilt angles range from 0–53°. In the fourth O2- site, O2- is bonded to two equivalent Ba2+, three Pr3+, and one Ni+2.50+ atom to form distorted OBa2Pr3Ni octahedra that share corners with sixteen OBaPr3Ni2 octahedra, edges with six OBaPr4Ni octahedra, and faces with four equivalent OBaPr3Ni2 octahedra. The corner-sharing octahedra tilt angles range from 17–52°. In the fifth O2- site, O2- is bonded to one Ba2+, three Pr3+, and two Ni+2.50+ atoms to form distorted OBaPr3Ni2 octahedra that share corners with eleven OBaPr4Ni octahedra, edges with two equivalent OBaPr3Ni2 octahedra, and faces with seven OBaPr4Ni octahedra. The corner-sharing octahedra tilt angles range from 5–55°.